Question 1

The upper and lower control limits for a component are 0.150 cm. and 0.120 cm., with a process target of .135 cm. The process standard deviation is 0.004 cm. and the process average is 0.138 cm. What is the process capability index?

Accepted Answer

The answer of The upper and lower control limits for...

Question 2

The quality control technician grew weary of measuring pistons that came off the line, so he decided to make a fixture that would tell him whether the piston fell within product specifications. The fixture had two holes, one the exact width of the upper specification (24 cm) and one slightly smaller than the lower specification (21 cm). If the piston fit through the smaller hole, it would be too small and therefore rejected. If the piston didn't fit through the larger hole, it was too large and would be rejected. Just to test his idea, he used the traditional measurement system and his new system on the next eight samples. The data and the two charts he constructed are shown below. Why aren't the plotted points forming similar shapes between the two graphs? Evaluate the advantages and disadvantages of his proposed system.

Accepted Answer

The answer of The quality control technician grew weary of...

Question 3

Samples of size 4 were taken from a process that had a target of 25 ounces with upper and lower specification limits of 30 ounces and 20 ounces respectively. Create the appropriate control charts and determine whether the process is in control.

Accepted Answer

The answer of Samples of size 4 were taken from...

Question 4

How does SPC help companies implement continuous improvement programs?

Accepted Answer

The answer of How does SPC help companies implement continuous...

Question 5

A process with a target of 25 was used to generate the following data points. Is the process properly centered?

Accepted Answer

The answer of A process with a target of 25...

Question 6

A bank randomly looks at loan applications and checks them for errors. Ten applications and the number of errors identified on the applications are found in the following table. When the process is working correctly, the average number of errors found is 2. Construct a c-chart to determine if the process is in control.

Accepted Answer

The answer of A bank randomly looks at loan applications...

Question 7

Construct a 3-sigma $ \bar{x} $ 
and R-chart for the length in centimeters of a part from the following table.

Accepted Answer

The answer of Construct a 3-sigma $ \bar{x} $ 
and...

Question 8

A metal-cutting operation has a target value of 20 and consistently averages 19.8 with a standard deviation of 0.5. The design engineers have established an upper specification limit of 22 and a lower specification limit of 18. What is the process capability index?

Accepted Answer

The process capability index (Cpk) is a measure of how well a process meets specifications. It is calculated as the minimum of the upper and lower specification limits minus the process mean, divided by three times the process standard deviation. In this case, the Cpk is calculated as (22 - 19.8) / (3 * 0.5) = 1.20.

Question 9

A metal-cutting operation has a target value of 20 and consistently averages 19.8 with a standard deviation of 0.5. The design engineers have established an upper specification limit of 22 and a lower specification limit of 18. Which statement concerning this process is True?

Accepted Answer

The process capability ratio (Cp) and the process capability index (Cpk) are both measures of how well a process can meet its specification limits. Cp is calculated using the formula Cp = (USL - LSL) / (6σ), and Cpk is the minimum of [(USL - mean) / (3σ)] and [(mean - LSL) / (3σ)]. Given the data, Cp = (22 - 18) / (6*0.5) = 4 / 3 = 1.33, not 1.46, making A incorrect. For Cpk, since the process mean is 19.8, the minimum of [(22 - 19.8) / (3*0.5)] and [(19.8 - 18) / (3*0.5)] must be calculated, which would not result in 1.33 exactly, making B incorrect. The statement "The process is in control" (C) cannot be determined solely based on the given information, as being in control refers to statistical control, which requires analysis of control charts and not just capability indices. Therefore, D is the correct choice.

Question 10

Process capability can be addressed when:

Accepted Answer

Process capability analysis measures whether a process is capable of producing output within the specified tolerance limits. It is only meaningful to conduct process capability analysis when a process is in statistical control, meaning that the variation is due to inherent factors in the process, as opposed to assignable causes such as machine malfunctions, variations in raw materials, or operator errors. If assignable causes are present, the process is not stable, and process capability analysis would not be useful. If the nominal value equals the tolerance, it would indicate that the process is performing as expected, but it does not mean the process is in control or capable.

Question 11

Thermostats are subjected to rigorous testing before they are shipped to air conditioning technicians around the world. Results from the last five samples are shown in the table. Is the process under control?

Accepted Answer

The answer of Thermostats are subjected to rigorous testing before...

Question 12

Using a value of 0.729 for the A₂ lookup from Table 5.1 yields:
UCL = 24.6 + 0.729*5.73 = 28.8
LCL = 24.6 - .729*5.73 = 20.4
  
The chart is in control.
-A professor records the number of students who complain each week throughout the semester. If the class size is forty students, what are 3-sigma control limits for this class? Construct a control chart and interpret the data.

Accepted Answer

The answer of Using a value of 0.729 for the...

Question 13

Hassan was the company plotter. Give him any data set and he could plot a graph that was not only accurate, but also aesthetically pleasing. One afternoon he took some attribute data and plotted it as a p-chart. When Saba, his supervisor, saw the plot he insisted it be discarded and in its place a c-chart should be constructed. Hassan made the c-chart and noticed that when he placed the two charts one on top of the other, the lines created by the data points were exactly the same shape. Has our plotting colleague made a mistake? If not, why should there be these two types of charts when the data generate identical lines?

Accepted Answer

The answer of Hassan was the company plotter. Give him...

Question 14

The management of a line that fills cereal boxes wants the box filled at 32.2 ounces. When the process is in control, the standard deviation is .1 ounces.
a. Construct the upper and lower control limits for a 3-sigma x-bar chart using a sample size of five.
b. The results from the last 10 samples follow. Is the process in control?

Accepted Answer

The answer of The management of a line that fills...

Question 15

Discuss the situations under which each of the following charts would be best: $ \bar{x} $ chart, p-chart, and c-chart.

Accepted Answer

The answer of Discuss the situations under which each of...

Question 16

The defect rate for a product has historically been about 2.0%. What are the upper and lower control chart limits if you wish to use a sample size of 100 and 3-sigma limits?

Accepted Answer

The answer of The defect rate for a product has...

Question 17

MKS Inc., produces meter sticks that have a target length of 100 centimeters with upper and lower specification limits of 100.05 and 99.95 centimeters respectively. Their existing process produces meter sticks with an average length of 99.97 centimeters and a standard deviation of 0.015 centimeters. What is their process capability index?

Accepted Answer

The answer of MKS Inc., produces meter sticks that have...

Question 18

The upper and lower specifications for a service are 10 min. and 8 min., respectively. The process average is 9 min. and the process capability ratio is 1.33. What is the process standard deviation?

Accepted Answer

The answer of The upper and lower specifications for a...

Question 19

MKS Inc., produces meter sticks that have a target length of 100 centimeters with upper and lower specification limits of 100.05 and 99.95 centimeters respectively. They are considering the purchase of a new machine that can hold a process output average exactly to target with a standard deviation of 0.02. Which would their process capability index be if they splurged and purchased the new machine?

Accepted Answer

The answer of MKS Inc., produces meter sticks that have...

Question 20

Process capability determines whether a process is capable of producing the product or services that customers demand.

Accepted Answer

Process capability is the ability of a process to produce the products or services that meet customer requirements in terms of quality, quantity, and lead time. It is determined by analyzing the process performance data and assessing whether the process is stable, predictable, and able to meet the customer's specifications. If the process is capable, it can produce products or services that meet or exceed customer expectations with consistency and reliability.

Quiz 3: Quality and Performance

The upper and lower control limits for a component are 0.150 cm. and 0.120 cm., with a process target of .135 cm. The process standard deviation is 0.004 cm. and the process average is 0.138 cm. What is the process capability index?

Samples of size 4 were taken from a process that had a target of 25 ounces with upper and lower specification limits of 30 ounces and 20 ounces respectively. Create the appropriate control charts and determine whether the process is in control.

How does SPC help companies implement continuous improvement programs?

A process with a target of 25 was used to generate the following data points. Is the process properly centered?

Construct a 3-sigma $\bar{x}$ and R-chart for the length in centimeters of a part from the following table. $Construct a 3-sigma \bar{x} and R-chart for the length in centimeters of a part from the following table.$

A metal-cutting operation has a target value of 20 and consistently averages 19.8 with a standard deviation of 0.5. The design engineers have established an upper specification limit of 22 and a lower specification limit of 18. What is the process capability index?

A metal-cutting operation has a target value of 20 and consistently averages 19.8 with a standard deviation of 0.5. The design engineers have established an upper specification limit of 22 and a lower specification limit of 18. Which statement concerning this process is True?

Process capability can be addressed when:

Thermostats are subjected to rigorous testing before they are shipped to air conditioning technicians around the world. Results from the last five samples are shown in the table. Is the process under control?

Discuss the situations under which each of the following charts would be best: $\bar{x}$ chart, p-chart, and c-chart.

The defect rate for a product has historically been about 2.0%. What are the upper and lower control chart limits if you wish to use a sample size of 100 and 3-sigma limits?

The upper and lower specifications for a service are 10 min. and 8 min., respectively. The process average is 9 min. and the process capability ratio is 1.33. What is the process standard deviation?

Process capability determines whether a process is capable of producing the product or services that customers demand.

Quiz 3: Quality and Performance

The upper and lower control limits for a component are 0.150 cm. and 0.120 cm., with a process target of .135 cm. The process standard deviation is 0.004 cm. and the process average is 0.138 cm. What is the process capability index?

Samples of size 4 were taken from a process that had a target of 25 ounces with upper and lower specification limits of 30 ounces and 20 ounces respectively. Create the appropriate control charts and determine whether the process is in control.

How does SPC help companies implement continuous improvement programs?

A process with a target of 25 was used to generate the following data points. Is the process properly centered?

Construct a 3-sigma xˉ \bar{x} xˉ and R-chart for the length in centimeters of a part from the following table.

A metal-cutting operation has a target value of 20 and consistently averages 19.8 with a standard deviation of 0.5. The design engineers have established an upper specification limit of 22 and a lower specification limit of 18. What is the process capability index?

A metal-cutting operation has a target value of 20 and consistently averages 19.8 with a standard deviation of 0.5. The design engineers have established an upper specification limit of 22 and a lower specification limit of 18. Which statement concerning this process is True?

Process capability can be addressed when:

Thermostats are subjected to rigorous testing before they are shipped to air conditioning technicians around the world. Results from the last five samples are shown in the table. Is the process under control?

Discuss the situations under which each of the following charts would be best: xˉ \bar{x} xˉ chart, p-chart, and c-chart.

The defect rate for a product has historically been about 2.0%. What are the upper and lower control chart limits if you wish to use a sample size of 100 and 3-sigma limits?

The upper and lower specifications for a service are 10 min. and 8 min., respectively. The process average is 9 min. and the process capability ratio is 1.33. What is the process standard deviation?

Process capability determines whether a process is capable of producing the product or services that customers demand.

Construct a 3-sigma $\bar{x}$ and R-chart for the length in centimeters of a part from the following table. $Construct a 3-sigma \bar{x} and R-chart for the length in centimeters of a part from the following table.$

Discuss the situations under which each of the following charts would be best: $\bar{x}$ chart, p-chart, and c-chart.